Rotation mechanism for percussive tools



Aug. 7, 1934. c. c HANSEN 1,969,368

ROTATION MECHANISM FOR PERCUSSIVE TOOLS Filed July 10, 1931 INVENTOR.61km" ed CHM/Sew.

HIS ATTORNEY Patented Aug. 7, 1934 UNITED STATES ROTATION MECHANISM FOR'PERCUSSIVE.

roons Charles C. Hansen, Easton, Pa., assignor to Ingersoll-RandCompany, Jersey City, N. J., a corpora'tion of New Jersey ApplicationJuly 10, 1931, Serial N0..549,865

2 Claim.

This invention relates to percussive tools, but

' t plifled and durable rotation mechanism for ef-.

' parts, 7

Figure 1 is a sectionalelevation of a rock drill.

fecting a step by step rotative movement of the working implementbetween successive blows of the hammer piston of the tool.

Anotherobject is to effect engagement of the elements whereby such stepby step rotation is brought about through the medium of pressure fluid,and a further object is to assure engagement of the rotation :lockingdevices both during the operative and inoperative periods of the tool.

Other objects will be in part obvious and in part pointed outhereinafter. 1 j

In the accompanying drawing illustrating a preferred. form of theinvention and in which similar reference equippedwith rotation mechanismconstructed in accordance with the practice of the invention.

Figure 2 is a transverse view taken through Figure 1 ion the'line 2-2looking in the direction indicated by-the arrows, and

Figure 3 is a sectional elevation of a detail taken through Figure 1 onthe line 33 looking in the direction indicated by the arrows.

Referring more particularly to the drawing, A designates generally arock drill comprising a cylinder B, the interior of which constitutes apiston chamber C to accommodate a reciprocatory hammer piston D. Thepiston chamber C is provided in this instance with a free exhaust port Ewhich is controlled by the head, F of the piston D. 1

A closure is provided for the front end of the piston chamber C by afront head G havinga bore H which may serve as a guide for an extensionor stem J carried by the piston D. The stem.

J is shown provided with the usual flutes K to receive ribs L of a chuckO encased by the front head G wherein it may rotate freelyto effectrotative movement of a working implement (not shown) but which the saidchuck may be-adapted to accommodate in a well known manner.

In the rear end of the cylinder B is an enlarged bore P to receive,among other things, valve mechanism designated generally by Q andcomprising a valve chest R which is shown as consisting of a pair ofplates S and T. The plate T seats in the bottom of the bore P adjacentthe rear end of the piston chamber C for which it forms a closure andthe rear end ofthe plate T serves as a characters refer to similar,

seat for the plate S and also for a valve U of the oscillatory platetype arranged in a valve cha ber V in the plate S.

The valve U controls the admission of pressure fluid to the ends of thecylinder. Such pressure fluid in the present instance is conveyed to therear end of the cylinder by a rear inlet passage W in the plate T andbeing controlled by one wing of the valve U, and pressure fluid isconveyed to the front end of the piston chamber 0 by a front inletpassage X formed in the plate T and the cylinder B and being controlledby the other wing of the valve U. r

Arranged on the rear end of the cylinder, for which it forms a closure,is a back head Y which may be secured tothe cylinder as may also be thefront head G by the usual spring pressed side bolts (not shown). As anadditional function the back head Y serves as a casing for a throttlevalve Z illustrated as being of the rotary type and having a handle I)for its manipulation.

The throttle valve Z has the usual central bore or chamber c which maybe in constant communi-- cation with the source of pressure fluidsupply. In the wallof the throttle valve Z is a" port :1 whichin theopen position of the throttle valve registers with a passage e in. theback headand opening into a supply reservoir 1, also in the back head.By forming the supply reservoir 1 of annular shape a central plug g isformed in the back head Yand the front end it of said plug is.preferably flush with the corresponding 'end of a flange a of the backhead which projects into the rear end of the cylinder B.

As a preferred form of construction the plug g is provided at its frontend with a reduced portion It to receive a ring 0 which may bepress-fitted thereon. The outer periphery of the ring is of somewhatsmaller diameter than the outer bound.- ing surface of the supplyreservoir 1 wherewith it cooperates to define an annular outlet openingp for the supply reservoir.

The rotation mechanism constructed in accordance with the practice ofthe invention comprises the usual rotatable rifle bar q which extendsthrough the plates S and T and into the piston chamber C tointerlockingly engage the piston D in a well known manner. The rifle barq carries an integral head 1' which lies between the plate S and theback head Y and carries at its rear end a trunnion s which extends intoa bore t in the plug 9/ of the back head.

Preferably a bushing u is disposed in the plates S and T and around therifle bar q to serve as a renewable bearing surface for the rifle barand also to prevent uncontrolled admission of pressure fluid from thevalve chamber V into the rear end of the piston chamber 0.

Encircling the head r is a ratchet ring 1) which is seated with one endupon the plate S and acts with its other end as a seat for the back headY and the ring 0, both of which are accurately fitted to prevent leakageof pressure fluid between their surfaces and the cooperating surface ofthe ratchet ring 1). In the ratchet ring 1) are supply passages w toafford communication between the supply reservoir 1 and the valvechamber V.

The ratchet ring 1) may be suitably held against rotary movement in thebore P by a keyor pin a: seated in suitable registering groovesin theouter and inner surfaces of the ratchet ring '0 and the held inreadiness for engagement with the teeth 3' thehead r is provided withbores 4, that is, one bore for each pawl, to receive plungers 5 whichmay reciprocate freely within the bores 4 and bear with their outer endsagainst the pawls y.

The bores 4, in effect, serve as cylinders to the inner or rear ends ofwhich is supplied pressure fluid by passages 6 extending through thehead 1" and the trunnion s and registering with an annular groove 7 inthe plug 9'. In the back, head Y is a passage 8 which opens with one endinto the annular groove 7 and registers at its other end with an annulargroove 9 in the periphery of the throttle valve Z. I

The annular groove 9 maybe of such length that it will be in constantregistry with the passage 8 in all of the various positions which thethrottle valve 2 may occupy in practice and is also in constantcommunication with the chamber 0 in the throttle valve through a port'10 in the throttle valve.

The head r of the riflebar. q is of sufficiently smaller diameter thanthe'interior of the ratchet ring to permit the free and constantadmission of pressure fluid throughout the entire interior of theratchet ring during the operation of the rock drill. Such pressure fluidmay be admitted into the ratchet ring from any suitable source but ispreferably conveyed thereto by a passage 11 located in this instance inthe ring 0 and leading from the supply reservoir 1.

' Means are provided to effect a suitable reduction in the value of thepressure fluid within the ratchet rin 21, and which pressure fluid actsagainst the outer ends of the plungers 5, so that the pressure fluidacting against the inner ends of the plungers 5 may predominate to pressthe pawls y into engagement with the teeth 3. In furtherance of this endthe ratchet ring 21 is provided with an atmospheric vent 1.2 which alsoextends through the wall of the cylinder B. In the vent 12 is formed atapered seat 13 for a needle valve 14 which is threaded into the ratchetring 1) to control the vent 12.

The operation of the device is as follows: With the throttle valve inthe open position wherein the port cl registers with the passagee,pressure fluid will flow through the supply reservoir 1 and the supplyport w into the valve chamber V.

ratchet ring '0.

From there the pressure fluid will be, distributed to the ends of thepiston chamber C by the valve U in the usual manner to eifectreciprocation of the piston D.

At the same time pressure fluid will flow into the bores 4 through thepassages connecting said bores with the interior of the throttle valve Zand pressure fluid will also flow from the supply reserveoir 1 throughthe passage 11 into the By correctly adjusting the needle valve 14 thevalue of the pressure fluid within the ratchet ring 1: is constantlymaintained below the value of the pressure fluid within the bores 4 sothat a preponderating pressure may act against the inner ends of theplungers 5 to press the pawls y gently but positively into position toengage the teeth 3. The pressure differential which may obtain in thebores 4 and in the ratchet ring 1) may be determined by what may beconsidered desirable or by the nature of the'work for which the tool isemployed.

With the hammer piston D in operation and assuming it to be starting onits rearward strokeas illustrated in Figure 1, and with the pawlspressed into engagement or in position'to en-- gage the teeth 3, thehammer piston will describe a partial revolution during its rearwardstroke and, being connected through the chuck mechanisms 0 with theworking implement, will therefore shift the working implement to a newposition in the drill hole for a succeeding blow of the hammer piston. 7

Upon reversal of the piston D in the rear end of the piston chamber 0and during the subsequent forward stroke of the piston the rifle bar qwill be rotated a partial revolution. thus shifting the pawls y to a newposition in theratchet ring '0. This rotary movement of the rifle barmay be effected with a minimum resistance to theforce acting against thepiston D to drive it against the working implement. This is due to thefact that'only a comparatively light pressure is exerted against theinner ends of the plungers 5. The pawls will therefore pass lightly overthe teeth 3 instead of exerting a heavy drag thereon as would be thecase were only the in ner ends of the plungers 5 exposed to pressureWhenever the working implement becomes stuck in the drill hole thethrottle valve Z may be rotated to a position to out off the supply ofpressure fluid to the supply chamber V and the tool may then bemanipulated to-free the working implement, as is the usual practice inthe operation of hand held tools. In'the closed position of the throttlevalve'pressure fluid will be supplied to the bores 4 and such pressurefluid will hold the pawls y firmly in engagement with the ratchet ring1:. The entire rotation mechanism will then remain suitably interlockedso that prying or turning pressure may be applied to the rear extremityof the tool to free the working implement from the work.

- I claim: 7

1. A fluid actuated, percussive tool comprisin a casing, a hammerpiston, a rifle bar for the hammer piston, a ratchet ring encircling therifle bar, pawls carried by the rifle bar, fluid actuated plungers inthe rifle bar to actuate the pawls into engagement with the ratchetring, and means for constantly supplying pressure fluid to the plungersduring the operative and inoperative periods of the tool.

2. A fluid actuated percussive tool comprising a casing, a hammerpiston, a throttle valve for engagement with the ratchet ring, and.means including ports and passages for constantly supplying pressurcfluid to the plungers from the bore during the operative and inoperativeperiods of the tool CHARLES C. HANSEN.

